/
metric.go
47 lines (40 loc) · 1.47 KB
/
metric.go
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package util
import (
"fmt"
"log/slog"
"net/http"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
otelprom "go.opentelemetry.io/otel/exporters/prometheus"
"go.opentelemetry.io/otel/sdk/metric"
"go.opentelemetry.io/otel/sdk/resource"
)
// NewMeterProviderForResource creates a prometheus-based OTEL MeterProvider with a default resource
func NewMeterProviderForResource(r *resource.Resource) (*metric.MeterProvider, error) {
// Create the prometheus exporter
// For an example with more config options, see https://docs.daocloud.io/en/insight/06UserGuide/01quickstart/otel/meter/#create-an-initialization-function-using-the-opentelemetry-sdk
metricExp, err := otelprom.New()
if err != nil {
return nil, fmt.Errorf("failed to initialize prometheus exporter: %w", err)
}
mp := metric.NewMeterProvider(
metric.WithReader(metricExp),
metric.WithResource(r),
)
return mp, nil
}
// ServeMetrics starts an HTTP server to serve prometheus metrics
func ServeMetrics(address string) func() error {
return func() error {
slog.Info("serving metrics", "address", address)
mux := http.NewServeMux()
mux.Handle("/metrics", promhttp.HandlerFor(prometheus.DefaultGatherer, promhttp.HandlerOpts{EnableOpenMetrics: true}))
metricServer := &http.Server{
Addr: address,
ReadHeaderTimeout: 3 * time.Second, // fix for gosec G114
Handler: mux,
}
return metricServer.ListenAndServe()
}
}